(a) Field
An embodiment of the invention relates to an under-voltage lockout circuit. Particularly, the embodiment relates to an under-voltage lockout circuit that can be applied to an integrated circuit that controls a high voltage output in a power supply.
(b) Description of the Related Art
An under-voltage lockout circuit is used to an integrated circuit (hereinafter, referred to as a switch control circuit) that controls switching operation of a power supply. The under-voltage lockout circuit controls protection operation that stops operation of a switch control circuit when a driving voltage supplied to the switch control circuit is an under voltage. For example, an enable level of a gate signal of the switch control circuit can be determined according to the driving voltage.
A conventional under-voltage lockout circuit is connected to the driving voltage, and determines whether a voltage is an under-voltage by comparing the driving voltage with a predetermined reference range. In this case, when the driving voltage is in an abnormal range, that is, when the driving voltage is an under-voltage, a static current is generated in the under-voltage lockout circuit. That is, power consumption occurs in the under-voltage lockout circuit due to the static current even though protection operation is performed for under-voltage lockout. Then, the power consumption is increased.
In order to prevent the increase of the power consumption, a shut-down signal is externally supplied to the switch control circuit to stop operation of the under-voltage lockout circuit according to a conventional art. However, the shut-down signal should be converted to a voltage range appropriate to a switch control circuit applied to a power supply that supplies a high voltage. This causes increase of the switch control circuit in size, and power consumption is additionally occurred during the conversion.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.